Why doesn't zabbix see trap?

Question

linux

Good afternoon
There is equipment that can send SNMP trap v2. I want to put it on monitoring in zabbix (3.2)
I see that the ladders leave the piece of iron and come to zabbix on the right port, that is, the problem is not in the network.
Created a network node, added an SNMP interface.
For the test, I created 2 data elements with the snmptrap[] and snmptrap.fallback keys. Tried different types of information. But zabbix does not see any traps in the latest data. On the server there are other pieces of iron on which there are no problems with traps.
How to understand what zabbix does not like and why it does not associate a trap with a specific node?
Ladder example:

Answer 1

if I remember correctly, there seems to be a layer in the form of SNMPTRAPD, which receives the traps and puts them into a file. You need to make it work properly first.